join::NetlinkManager Class Reference

base class for netlink-based managers. More...

#include <netlinkmanager.hpp>

Inheritance diagram for join::NetlinkManager:

Collaboration diagram for join::NetlinkManager:

Classes
struct	PendingRequest
	pending synchronous request. More...

Public Member Functions
	NetlinkManager (uint32_t groups, Reactor *reactor=nullptr)
	create instance.
	NetlinkManager (const NetlinkManager &)=delete
	create instance by copy.
	NetlinkManager (NetlinkManager &&)=delete
	create instance by move.
NetlinkManager &	operator= (const NetlinkManager &)=delete
	assign instance by copy.
NetlinkManager &	operator= (NetlinkManager &&)=delete
	assign instance by move.
virtual	~NetlinkManager ()=default
	destroy instance.
Reactor *	reactor () const noexcept
	get the event loop reactor.

Protected Member Functions
void	start ()
	start listening for netlink events.
void	stop ()
	stop listening for netlink events.
int	sendRequest (struct nlmsghdr *nlh, bool sync, std::chrono::milliseconds timeout=std::chrono::seconds(5))
	send a netlink request, optionally waiting for the ack.
template<class Rep , class Period >
int	waitResponse (ScopedLock< Mutex > &lock, uint32_t seq, std::chrono::duration< Rep, Period > timeout)
	wait for specific netlink response.
virtual void	onReceive (int fd) override final
	method called when data are ready to be read on handle.
virtual void	onMessage (struct nlmsghdr *nlh)=0
	dispatch a single RTM_* message to the derived class.
void	notifyRequest (uint32_t seq, int error=0)
	notify a pending synchronous request.

Static Protected Member Functions
static void	addAttributes (struct nlmsghdr *nlh, int type, const void *data, int alen)
	add an attribute to a netlink message.
static struct rtattr *	startNestedAttributes (struct nlmsghdr *nlh, int type)
	open a nested attribute block.
static int	stopNestedAttributes (struct nlmsghdr *nlh, struct rtattr *nested)
	close a nested attribute block.
template<typename T , typename Flag >
static Flag	updateValue (T &oldVal, const T &newVal, Flag changed)
	update a value in place and report whether it changed.

Protected Attributes
std::unique_ptr< char[]>	_buffer
	internal read buffer.
std::atomic< uint32_t >	_seq
	sequence number.
std::unordered_map< uint32_t, std::unique_ptr< PendingRequest > >	_pending
	synchronous requests indexed by sequence number.
Mutex	_syncMutex
	protection mutex.
Reactor *	_reactor
	event loop reactor.

Static Protected Attributes
static constexpr size_t	_bufferSize = 16384
	internal buffer size.

Detailed Description

base class for netlink-based managers.

Constructor & Destructor Documentation

NetlinkManager() [1/3]

NetlinkManager::NetlinkManager	(	uint32_t	groups,
		Reactor *	reactor = nullptr )

create instance.

Parameters

groups	netlink multicast group bitmask to subscribe to.
reactor	event loop reactor.

NetlinkManager() [2/3]

join::NetlinkManager::NetlinkManager ( const NetlinkManager & )

delete

create instance by copy.

NetlinkManager() [3/3]

join::NetlinkManager::NetlinkManager ( NetlinkManager && )

delete

create instance by move.

~NetlinkManager()

virtual join::NetlinkManager::~NetlinkManager ( )

virtualdefault

destroy instance.

Member Function Documentation

addAttributes()

void NetlinkManager::addAttributes ( struct nlmsghdr * nlh, int type, const void * data, int alen )

staticprotected

add an attribute to a netlink message.

Parameters

nlh	netlink message header.
type	attribute type (RTA_*, IFA_*, NDA_*, …).
data	attribute payload.
alen	payload length in bytes.

notifyRequest()

void NetlinkManager::notifyRequest ( uint32_t seq, int error = 0 )

protected

notify a pending synchronous request.

Parameters

seq	sequence number of the completed request.
error	kernel error code (0 on success, positive errno).

onMessage()

virtual void join::NetlinkManager::onMessage ( struct nlmsghdr * nlh )

protectedpure virtual

dispatch a single RTM_* message to the derived class.

Parameters

nlh	the netlink message to process.

onReceive()

void NetlinkManager::onReceive ( int fd )

finaloverrideprotectedvirtual

method called when data are ready to be read on handle.

Parameters

fd	file descriptor.

Reimplemented from join::EventHandler.

operator=() [1/2]

NetlinkManager & join::NetlinkManager::operator= ( const NetlinkManager & )

delete

assign instance by copy.

operator=() [2/2]

NetlinkManager & join::NetlinkManager::operator= ( NetlinkManager && )

delete

assign instance by move.

reactor()

Reactor * NetlinkManager::reactor ( ) const

noexcept

get the event loop reactor.

Returns

pointer to the reactor.

sendRequest()

int NetlinkManager::sendRequest ( struct nlmsghdr * nlh, bool sync, std::chrono::milliseconds timeout = std::chrono::seconds (5) )

protected

send a netlink request, optionally waiting for the ack.

Parameters

nlh	netlink message to send.
sync	if true, block until NLMSG_ERROR/NLMSG_DONE is received.
timeout	maximum wait duration when sync is true (default: 5 seconds).

Returns

0 on success, -1 on failure.

start()

void NetlinkManager::start ( )

protected

start listening for netlink events.

startNestedAttributes()

struct rtattr * NetlinkManager::startNestedAttributes ( struct nlmsghdr * nlh, int type )

staticprotected

open a nested attribute block.

Parameters

nlh	netlink message header.
type	container attribute type.

Returns

pointer to the container rtattr (pass to stopNestedAttributes).

stop()

void NetlinkManager::stop ( )

protected

stop listening for netlink events.

stopNestedAttributes()

int NetlinkManager::stopNestedAttributes ( struct nlmsghdr * nlh, struct rtattr * nested )

staticprotected

close a nested attribute block.

Parameters

nlh	netlink message header.
nested	pointer returned by startNestedAttributes.

Returns

current message length.

updateValue()

template<typename T , typename Flag >

static Flag join::NetlinkManager::updateValue ( T & oldVal, const T & newVal, Flag changed )

inlinestaticprotected

update a value in place and report whether it changed.

Parameters

oldVal	value to update.
newVal	candidate new value.

Returns

true if the value was changed, false otherwise.

waitResponse()

template<class Rep , class Period >

int join::NetlinkManager::waitResponse ( ScopedLock< Mutex > & lock, uint32_t seq, std::chrono::duration< Rep, Period > timeout )

inlineprotected

wait for specific netlink response.

Parameters

lock	mutex previously locked by the calling thread.
seq	sequence number to wait for.
timeout	maximum wait duration.

Returns

0 on success, -1 on failure.

Member Data Documentation

_buffer

std::unique_ptr<char[]> join::NetlinkManager::_buffer

protected

internal read buffer.

_bufferSize

size_t join::NetlinkManager::_bufferSize = 16384

staticconstexprprotected

internal buffer size.

_pending

std::unordered_map<uint32_t, std::unique_ptr<PendingRequest> > join::NetlinkManager::_pending

protected

synchronous requests indexed by sequence number.

_reactor

Reactor* join::NetlinkManager::_reactor

protected

event loop reactor.

_seq

std::atomic<uint32_t> join::NetlinkManager::_seq

protected

sequence number.

_syncMutex

Mutex join::NetlinkManager::_syncMutex

protected

protection mutex.

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The documentation for this class was generated from the following files:

• fabric/include/join/netlinkmanager.hpp
• fabric/src/netlinkmanager.cpp